This work considers formulation of new classes of adaptive controllers for double-integrator type systems where the underlying system parameters are uncertain and the complete state-vector is not available for feedback. Given the parameter uncertainty within the system model, a "separation principle" cannot generally be invoked towards an observer geared towards reconstruction of the full state vector using only measured variables. In this report, controllers are designed for some important sub-classes of Euler-Lagrange type mechanical systems, where states are physically interpreted as position and velocity variables, and only the position part of the state vector is available as measured output. The typical approach to obtain velocity estimates using position interpolation (also known as dirty differentiation), is known to be strongly susceptible to measurement noise and therefore does not usually represent a robust option for feedback control implementation. The proposed control scheme achieves global asymptotic stability for system dynamics subject to the condition that velocity states appear within the governing dynamics in a linear fashion. This arguably restrictive condition is loosened for the special case of scalar system with friction non-linearity as is typical within hardware implementations. The objective is to study prototypical mechanical systems with non-linearity appearing in the velocity rate equations with the eventual applications envisioned towards the attitude control problem accounting for the gyroscopic non-linearity in the Euler rotational dynamics. Based on classical certainty equivalence approaches for adaptive control, one cannot readily deal with cross terms associated with parameter estimates and unmeasured states in the Lyapunov function derivative in order to make the Lyapunov function negative definite or negative semi-definite. However, employing a new approach, this obstacle is shown in this report to be circumvented for scalar systems. In order to generalize the methodology for higher-order dynamics, a filtered state approach is used. Specifically, an auxiliary variable is introduced which plays an important role in determining restrictions on the control parameters and analyzing the stability. The proposed approach helps to overcome the uniform detectability obstacle. Additionally, this work can be applied to uncertain linear systems where independent control inputs are applied on each of the velocity state dynamics. Lastly, the solution for the scalar is applied to the rotor speed control system and is extended to the case where Coulomb friction is considered in addition to viscous friction. Since a sign function can be approximated as a hyperbolic tangent, the tanh model is used for the Coulomb friction. A controller is developed with the assumption that the coefficients of these frictions are unknown. The proposed control is then verified with Educational Control Product Model 750 Control Moment Gyroscope, and the simulation and actual test results are compared. / text

Este trabalho aborda o desenvolvimento de um sistema de controle em malha fechada de torque e velocidade de rotação para testes de motores de combustão interna em uma bancada que possui um dinamômetro de correntes de Foucault. É apresentada uma revisão bibliográfica que abrange a fundamentação teórica básica sobre dinamômetro, alguns dos principais testes realizados em motores de combustão interna e técnicas de controle e instrumentação que estão sendo desenvolvidas por pesquisadores sobre o tema de controle de dinamômetro para testes de motores de combustão interna. O projeto surgiu com a necessidade do Laboratório de Motores da UFRGS realizar vários testes em motores a combustão tendo uma maior confiabilidade e rapidez para aquisição dos resultados. Este sistema está baseado num microcontrolador da família Atmega onde foram implementados os algoritmos de um controlador PID e um proporcional, que controlam respectivamente, os níveis de corrente contínua aplicadas no dinamômetro e o percentual de abertura da borboleta do motor combustão através de um motor de passo. A etapa de controle é executada no microcontrolador e uma interface gráfica foi implementada em Labview. Esta interface gráfica faz a leitura via porta serial dos dados do microcontrolador e traça suas curvas as salvando em arquivo, também se pode visualizar os sinais das temperaturas do motor e dinamômetro e nível de combustível do reservatório. A validação do controle desenvolvido foi comprovada através da verificação da convergência dos sinais para os valores de referência desejados. O controle propiciou também uma diminuição dos tempos para obtenção das respostas desejadas em comparação com o sistema anterior de controle manual. / This paper describes the development of a torque and rotation speed closed loop control system for internal combustion engine tests in a bench using a Foucault current dynamometer. A bibliographical review that encompasses basic dynamometer theoretical concepts, some of the most important tests applied to internal combustion engines, and control and instrumentation techniques currently under development on dynamometer testing for internal combustion engines is presented. This project needs to perform tests in combustion engines which would produce more dependable and faster results. The system herein developed is based on an Atmega-type microcontroller where algorithms of both a PID and a proportion controller, controlling respectively the levels of direct current applied through the dynamometer coils and the opening of an internal combustion engine throttle body by means of a step motor, were implemented. The control stage was done in the microcontroller and a graphic interface for a personal computer was created in Labview. This graphic interface facilitates the microcontroller data reading and traces its curves, saving them in a file; also, the engine and dynamometer temperature signals and the tank fuel level can be visualized. The validation of this control has been proved by the signal convergence check for desired reference values. Furthermore, the control has enabled a reduction in ideal answer time attainment as compared to the previous manual system.

Este trabalho aborda o desenvolvimento de um sistema de controle em malha fechada de torque e velocidade de rotação para testes de motores de combustão interna em uma bancada que possui um dinamômetro de correntes de Foucault. É apresentada uma revisão bibliográfica que abrange a fundamentação teórica básica sobre dinamômetro, alguns dos principais testes realizados em motores de combustão interna e técnicas de controle e instrumentação que estão sendo desenvolvidas por pesquisadores sobre o tema de controle de dinamômetro para testes de motores de combustão interna. O projeto surgiu com a necessidade do Laboratório de Motores da UFRGS realizar vários testes em motores a combustão tendo uma maior confiabilidade e rapidez para aquisição dos resultados. Este sistema está baseado num microcontrolador da família Atmega onde foram implementados os algoritmos de um controlador PID e um proporcional, que controlam respectivamente, os níveis de corrente contínua aplicadas no dinamômetro e o percentual de abertura da borboleta do motor combustão através de um motor de passo. A etapa de controle é executada no microcontrolador e uma interface gráfica foi implementada em Labview. Esta interface gráfica faz a leitura via porta serial dos dados do microcontrolador e traça suas curvas as salvando em arquivo, também se pode visualizar os sinais das temperaturas do motor e dinamômetro e nível de combustível do reservatório. A validação do controle desenvolvido foi comprovada através da verificação da convergência dos sinais para os valores de referência desejados. O controle propiciou também uma diminuição dos tempos para obtenção das respostas desejadas em comparação com o sistema anterior de controle manual. / This paper describes the development of a torque and rotation speed closed loop control system for internal combustion engine tests in a bench using a Foucault current dynamometer. A bibliographical review that encompasses basic dynamometer theoretical concepts, some of the most important tests applied to internal combustion engines, and control and instrumentation techniques currently under development on dynamometer testing for internal combustion engines is presented. This project needs to perform tests in combustion engines which would produce more dependable and faster results. The system herein developed is based on an Atmega-type microcontroller where algorithms of both a PID and a proportion controller, controlling respectively the levels of direct current applied through the dynamometer coils and the opening of an internal combustion engine throttle body by means of a step motor, were implemented. The control stage was done in the microcontroller and a graphic interface for a personal computer was created in Labview. This graphic interface facilitates the microcontroller data reading and traces its curves, saving them in a file; also, the engine and dynamometer temperature signals and the tank fuel level can be visualized. The validation of this control has been proved by the signal convergence check for desired reference values. Furthermore, the control has enabled a reduction in ideal answer time attainment as compared to the previous manual system.

Este trabalho aborda o desenvolvimento de um sistema de controle em malha fechada de torque e velocidade de rotação para testes de motores de combustão interna em uma bancada que possui um dinamômetro de correntes de Foucault. É apresentada uma revisão bibliográfica que abrange a fundamentação teórica básica sobre dinamômetro, alguns dos principais testes realizados em motores de combustão interna e técnicas de controle e instrumentação que estão sendo desenvolvidas por pesquisadores sobre o tema de controle de dinamômetro para testes de motores de combustão interna. O projeto surgiu com a necessidade do Laboratório de Motores da UFRGS realizar vários testes em motores a combustão tendo uma maior confiabilidade e rapidez para aquisição dos resultados. Este sistema está baseado num microcontrolador da família Atmega onde foram implementados os algoritmos de um controlador PID e um proporcional, que controlam respectivamente, os níveis de corrente contínua aplicadas no dinamômetro e o percentual de abertura da borboleta do motor combustão através de um motor de passo. A etapa de controle é executada no microcontrolador e uma interface gráfica foi implementada em Labview. Esta interface gráfica faz a leitura via porta serial dos dados do microcontrolador e traça suas curvas as salvando em arquivo, também se pode visualizar os sinais das temperaturas do motor e dinamômetro e nível de combustível do reservatório. A validação do controle desenvolvido foi comprovada através da verificação da convergência dos sinais para os valores de referência desejados. O controle propiciou também uma diminuição dos tempos para obtenção das respostas desejadas em comparação com o sistema anterior de controle manual. / This paper describes the development of a torque and rotation speed closed loop control system for internal combustion engine tests in a bench using a Foucault current dynamometer. A bibliographical review that encompasses basic dynamometer theoretical concepts, some of the most important tests applied to internal combustion engines, and control and instrumentation techniques currently under development on dynamometer testing for internal combustion engines is presented. This project needs to perform tests in combustion engines which would produce more dependable and faster results. The system herein developed is based on an Atmega-type microcontroller where algorithms of both a PID and a proportion controller, controlling respectively the levels of direct current applied through the dynamometer coils and the opening of an internal combustion engine throttle body by means of a step motor, were implemented. The control stage was done in the microcontroller and a graphic interface for a personal computer was created in Labview. This graphic interface facilitates the microcontroller data reading and traces its curves, saving them in a file; also, the engine and dynamometer temperature signals and the tank fuel level can be visualized. The validation of this control has been proved by the signal convergence check for desired reference values. Furthermore, the control has enabled a reduction in ideal answer time attainment as compared to the previous manual system.

<p> The voltage, current and torque equations of a two phase generalized machine are reviewed and the transformation are derived for the equivalent two phase commutator primitive of the three-phase slip-ring machine. The design of an SCR controlled inverter for speed variation of the two phase machine is presented and a method of comparing theoretical with practical values described.</p> / Thesis / Master of Engineering (MEngr)

No description available.

In the United States, speeding is considered to be a contributing factor in about 30 percent of fatal crashes (US DOT, 2000). In an attempt to reduce speeds on roadway segments where speed is considered to be a safety concern, various low cost countermeasures have been investigated. Such countermeasures include pavement markings that give a psychological appearance of narrowing and/or increasing speed have been considered as a relatively low-cost treatment. Perceptual cues are one potential method of influencing motorists to slow down, and ultimately, to save lives. These perceptual techniques might be useful at lowering speeds in a variety of driving situations such as work zones, curves, roundabouts, and toll plazas. Evaluations are required in order to determine the effectiveness of these various treatments at reducing speeds. This research project explored several possible perceptual countermeasures to try on the approaches to curves for reducing speeds. It was ultimately decided to evaluate the effects of peripheral transverse lines in reducing speeds. Although there have been some limited evaluations of peripheral transverse markings in previous studies, no significant field evaluation has been performed and a recommended design for the markings has not been discussed. The projected results of the research effort is to determine pavement marking treatments with a high probability of success at reducing speeds, develop and design peripheral transverse markings based on site considerations, determine the effectiveness of the markings in the field, determine optimal pavement marking design using a driving simulator, and use a controlled research environment to finalize the design. This dissertation contributes to the body of knowledge on speed reduction research through the development of low cost speed reduction strategies, the design of peripheral transverse lines for varying geometric conditions, evaluation of these treatments in the field, in the simulator, and on a controlled roadway, and to finally compare the benefits of each of the evaluation approaches. In the field, peripheral transverse lines spaced at a frequency of 4 bars per second were evaluated in New York, Mississippi, and Texas. The markings were applied on approaches to curves in both rural and urban environments on both multi-lane and two-lane roadways. The authors concluded that overall, the pavement markings reduced speeds up to 59% compared to the baseline in the short term and 24% in the long term on overall vehicle speeds. When evaluating design alternatives of peripheral transverse markings, a follow-up study was performed and compared baseline conditions to markings spaced at a constant interval, exponentially closer, at two bars per second, and at four bars per second. The peripheral transverse lines were effective in reducing centerline encroachment; however, the results were inconclusive as to which particular marking spacing pattern was most effective. There was a large amount of variability in driving speeds using the driving simulator which made it ineffective at comparing designs. The third evaluation was performed at the Virginia Tech Smart Road in which reductions in speed were compared to the baseline at two locations. While one curve had large preview distances and no effect due to the treatments, speed reductions on a freeway ramp type of curve resulted in a speed reduction 42% greater than the reduction in the baseline condition. There are several advantages and disadvantages to evaluations in the field, simulator, and at a controlled research setting which are summarized in this dissertation. Overall, all three have potential of looking at different elements, but it was determined that variability when measuring speed in the driving simulator makes it more challenging as a tool for measuring speed reductions. / Ph. D.

In step with development of advanced, cost effective semiconductors and electrical motor drive components, the Switched Reluctance Machine (SRM) has become the center of public attention. Interest in a single-phase SRM has arisen in many places, especially because of its low cost applications. However, some drawbacks have plagued single-phase SRM: the lack of self-starting capability and restricted operation conditions. This thesis presents a four-quadrant operation SRM drive system with a single controllable switch for two phase configuration. The SRM's configuration has four main stator poles, four rotor poles, and four auxiliary stator poles. Because of this special arrangement, a four-quadrant operation with a given power converter topology and proposed control algorithms has been realized. The focus of the paper is to realize a four-quadrant operation with a single-switch converter based SRM. In addition, this research resulted in a new self-starting scheme without adding permanent magnets. Simulation results and experimental results utilizing the control algorithm verify the performance of the system. / Master of Science

O objetivo deste trabalho consiste na implementação de arquiteturas de sistema inteligentes em Processadores Digitais de Sinais (DSP) visando, sobretudo, o controle em tempo real de motores de indução trifásicos. Para tanto, propõe-se uma abordagem fuzzy para o controle de velocidade de motores de indução trifásicos baseado na metodologia de ajuste de tensão e freqüência (Volts/Hertz) proveniente de um inversor PWM, de modo que o fluxo no entreferro seja mantido constante. O enfoque principal consiste no desenvolvimento do sistema de controle em hardware considerando o estudo dinâmico do controlador frente às variações de conjugado de carga, cujo desempenho da metodologia proposta será avaliado mediante simulações computacionais e ensaios experimentais realizados em laboratório. / The objective of this work consists of the implementation of intelligent system architecture in Digital Signal Processor (DSP) aiming at the real-time three-phase induction motor control. Therefore, a fuzzy logic speed control drive system for three-phase induction motor is proposed, whereas the control methodology is based on voltage and frequency (Volts/Hertz) adjustment of a PWM inverter so that the airgap flux maintains constant. The main focus concerns about hardware development of the control system considering the controller dynamic response study in relation to load torque variations, from which the proposed methodology performance is evaluated by means of computational simulation and experimental results obtained in laboratory.

Neste trabalho é proposto um estudo envolvendo o controle vetorial do Motor de Indução Trifásico, compreendendo o uso da teoria de modos deslizantes nas malhas de controle de fluxo e velocidade na estratégia de Controle Vetorial por Orientação Indireta de Campo (Indirect Field Oriented Control, IFOC), visando sobretudo, melhorar tanto o desempenho dinâmico quanto o problema de chattering. Para tanto, aborda-se o uso de uma função de chaveamento suave, analisando suas características perante o uso de diferentes superfícies de deslizamento. Com base nessas análises, tem-se a proposta de um controlador por modos deslizantes integral, englobando o uso de uma superfície de deslizamento integral em conjunto com um método de anti-windup, sendo tal método baseado em uma função triangular. Para verificar a atratividade às superfícies de fluxo e velocidade, é realizada uma investigação quanto ao uso de uma parcela paramétrica como ação de controle, dada pelo termo equivalente. Com o objetivo de analisar a topologia de controle proposta, resultados são obtidos por meio de simulação e de uma bancada experimental considerando diferentes condições de operação. Desta forma, os resultados foram divididos em testes, visando abordar o problema do chattering e diferenças do controlador proposto perante os convencionais. De maneira geral, a topologia de controle apresentou resultados melhores aos encontrados na literatura, podendo ser uma opção em sistemas que requerem acionamento de alto desempenho dinâmico. / This work deals with the vector control in a three-phase induction motor, applying the sliding mode theory to both the flux and the speed control loops in the Indirect Field Oriented Control strategy. It aims to improve the dynamic performance regarding the chattering problem. Therefore, the use of a smooth switching function is addressed, analyzing the outcomes achieved by different sliding surfaces. Based on these analysis, an Integral Sliding Mode Controller is proposed employing an integral sliding surface along with an anti-windup method based on a triangular function. In order to verify the attractiveness of the flux and the speed surfaces, an investigation regarding the use of a parametric portion as control action is carried out. The proposed control strategy is verified by means of simulations and experiments on test bench for different operating conditions. This way, the results are split in tests aiming to approach chattering problems and the differences between the proposed and traditional control strategies. Genarally, the outcomes of the proposed topology are better with those found on literature, pointing it as a viable choice to drive high dynamic performance demanding systems.